MySQL - Università di Enna A.A. 2005-06 http://www.ossez.com/forum.php?mod=viewthread&tid=26898&fromuid=426 (出处: OSSEZ)

1. Mysql
Basi di Dati
Universitàdi Enna A.A. 2005/06

2. Intro
 MySQL® and the MySQL logo are registered trademarks of
MySQL AB (a Swedish company)
 The MySQL® software delivers a very fast, multi-threaded, multi-
user, and robust SQL (Structured Query Language) database
server
 The MySQL Web site (http://www.mysql.com/) provides the
latest information about MySQL and MySQL AB
 the “AB” part of the company name is the acronym for the
Swedish “aktiebolag,” or “stock company”

3. License
 The MySQL software is Dual Licensed
Users can choose to use the MySQL software as an Open
Source product under the terms of the GNU General Public
License
Users can purchase a standard commercial license from
MySQL AB
 See http://www.mysql.com/company/legal/licensing/
for more information on our licensing policies.

4. Documentation
 The MySQL Database Software is under constant
development, and the Reference Manual is updated
frequently as well. The most recent version of the
manual is available online in searchable form at
http://dev.mysql.com/doc/
 Formats available:
 HTML
 PDF
 CHM

5. Operating Systems Supported by MySQL
 It is possible to port MySQL to all modern systems
that have a C++ compiler and a working
implementation of POSIX threads
 Thread support is needed for the server. To compile
only the client code, the only requirement is a C++
compiler
 “We use and develop the software ourselves primarily
on Linux (SuSE and Red Hat), FreeBSD, and Sun
Solaris (Versions 8 and 9)”

6. Operating Systems Supported by MySQL
 MySQL has been reported to compile successfully on
the following operating systems:
 AIX 4.x, 5.x
 Amiga
 BSDI 2.x
 Digital Unix 4.x
 FreeBSD 2.x, 3.x, 4.x
 Mac OS X
 Windows 9x, Me, NT, 2000, XP, and 2003

7. Installing MySQL on Windows
 A native Windows version of MySQL has been
available from MySQL AB since version 3.21 and
represents a sizable percentage of the daily
downloads of MySQL
 The installer for the Windows version of MySQL 5.0,
combined with a GUI Configuration Wizard,
automatically installs MySQL, creates an option file,
starts the server, and secures the default user accounts

8. Installing MySQL on Windows
 MySQL 5.0 for Windows is available in three distribution
formats:
 The binary distribution contains a setup program that installs
everything you need so that you can start the server immediately
 The source distribution contains all the code and support files for
building the executables using the Visual Studio 2003 compiler system
 Generally speaking, you should use the binary distribution. It
is simpler to use than the others, and you need no additional
tools to get MySQL up and running

9. Installing MySQL on Windows
 A copy of the MySQL binary distribution for
Windows, which can be downloaded from
http://dev.mysql.com/downloads/
 You may also have the following optional
requirements:
If you plan to connect to the MySQL server via ODBC,
you also need a Connector/ODBC driver
If you need tables with a size larger than 4GB, install
MySQL on an NTFS or newer filesystem

10.  For MySQL 5.0, there are three installation packages
to choose from when installing MySQL on Windows.
The packages are as follows:
 Essential package
 Complete package
 Noinstall archive
 The Essentials package is recommended for most
users
Installing MySQL on Windows

11.  The following entries are created within the new
Start menu section:
MySQL Command Line Client : This is a shortcut to the
mysql command-line client and is configured to connect as
the root user. The shortcut prompts for a root user password
when connecting
MySQL Server Instance Config Wizard : This is a
shortcut to the MySQL Configuration Wizard. Use this
shortcut to configure a newly installed server, or to re-
configure an existing server
MySQL Documentation : This is a link to the MySQL
server documentation that is stored locally in the MySQL
server installation directory. This option is not available
when the MySQL server is installed using the Essentials
installation package.
Installing MySQL on Windows

12. The Main Features of MySQL
Written in C and C++
Tested with a broad range of different
compilers
Works on many different platforms
Uses GNU Automake, Autoconf, and Libtool
for portability
APIs for C, C++, Eiffel, Java, Perl, PHP,
Python, Ruby, and Tcl are available
…

13. Column Types
 Many column types:
signed/unsigned integers 1, 2, 3, 4, and 8 bytes long
FLOAT, DOUBLE
CHAR, VARCHAR
TEXT
BLOB
DATE, TIME, DATETIME, TIMESTAMP, YEAR
SET, ENUM
 Fixed-length and variable-length records

14. Statements and Functions
 Full operator and function support in the SELECT
and WHERE clauses of queries.
 Full support for SQL GROUP BY and ORDER BY
clauses. Support for group functions (COUNT(),
COUNT(DISTINCT ...), AVG(), STD(), SUM(),
MAX(), MIN()
 Support for LEFT OUTER JOIN and RIGHT
OUTER JOIN
 Support for aliases on tables and columns as required
by standard SQL

15. Statements and Functions (2)
 DELETE, INSERT, REPLACE, and UPDATE return the
number of rows that were changed (affected)
 The MySQL-specific SHOW command can be used to
retrieve information about databases, database engines, tables,
and indexes. The EXPLAIN command can be used to
determine how the optimizer resolves a query
 Function names do not clash with table or column names. For
example, ABS is a valid column name. The only restriction is
that for a function call, no spaces are allowed between the
function name and the ‘(’ that follows it
 You can mix tables from different databases in the same query

16. Limits
Handles large databases.
“We use MySQL Server with databases that
contain 50 million records …”
“… We also know of users who use MySQL
Server with 60,000 tables and about 5,000,000,000
rows …”

17. Connectivity
 Clients can connect to the MySQL server using
TCP/IP sockets on any platform
 The Connector/ODBC (MyODBC) interface provides
MySQL support for client programs that use ODBC
(Open Database Connectivity) connections.
For example, you can use MS Access to connect to your
MySQL server.
The Connector/J interface provides MySQL
support for Java client programs that use
JDBC connections

18. How Big MySQL Tables Can Be
 MySQL 3.22 had a 4GB (4 gigabyte) limit on table
size.
 With the MyISAM storage engine in MySQL 3.23,
the maximum table size was increased to 65536
terabytes (2567 – 1 bytes).
 With this larger allowed table size, the maximum
effective table size for MySQL databases is usually
determined by operating system constraints on file
sizes, not by MySQL internal limits

19.  The following table lists some examples of operating
system file-size limits. This is only a rough guide and
is not intended to be definitive
 Win32 (FAT/FAT32) 2GB/4GB
 Win32 (NTFS) 2TB
 Linux 2.2-Intel 2GB
 Linux 2.4+ (ext3) 4TB
 Windows users please note: FAT and VFAT (FAT32)
are not considered suitable for production use with
MySQL. Use NTFS instead
How Big MySQL Tables Can Be

20. Connecting to and Disconnecting from
the Server
 To connect to the server, you will usually need to
provide a MySQL username when you invoke mysql
and, most likely, a password. If the server runs on a
machine other than the one where you log in, you will
also need to specify a hostname
 shell> mysql -h host -u user –p
Enter password: ********

21. Connecting to and Disconnecting from
the Server
 shell> mysql -h host -u user –p
Enter password: ********
 host and user represent the hostname where your
MySQL server is running and the username of your
MySQL account
 The ******** represents your password; enter it
when mysql displays the Enter password: prompt.

22. Connecting to and Disconnecting from
the Server

23. Connecting to and Disconnecting from
the Server
 Some MySQL installations allow users to connect as
the anonymous (unnamed) user to the server running
on the local host.
 If this is the case on your machine, you should be
able to connect to that server by invoking mysql
without any options:
 shell> mysql

24. Connecting to and Disconnecting from
the Server
 After you have connected successfully, you can
disconnect any time by typing QUIT (or EXIT) at
the mysql > prompt:
 shell> QUIT
Bye
 shell> EXIT
Bye
 On Unix, you can also disconnect by pressing Control-D

25. Entering Queries
 mysql> SELECT VERSION( ), CURRENT_DATE;

26. Notes
• When you issue a command, mysql sends it to the
server for execution and displays the results, then
prints another mysql> prompt to indicate that it is
ready for another command.

27. Notes (2)
 mysql displays query output in tabular form (rows
and columns). The first row contains labels for the
columns. The rows following are the query results.

28. Notes (3)
 mysql shows how many rows were returned and how
long the query took to execute, which gives you a
rough idea of server performance

29. Entering Queries
 Keywords may be entered in any lettercase. The
following queries are equivalent:
 mysql> SELECT VERSION(), CURRENT_DATE;
 mysql> select version(), current_date;
 mysql> SeLeCt vErSiOn(), current_DATE;

30. • Here's another query. It demonstrates that you can use
mysql as a simple calculator
Entering Queries

31.  You can even enter multiple statements on a single
line. Just end each one with a semicolon
Entering Queries

32.  A command need not be given all on a single line, so
lengthy commands that require several lines are not a
problem
 mysql determines where your statement ends by
looking for the terminating semicolon, not by looking
for the end of the input line
Entering Queries

33. Entering Queries

34.  The following table shows each of the prompts you may
see and summarizes what they mean about the state that
mysql is in:
mysql> Ready for new command.
-> Waiting for next line of multiple-line command
‘> Waiting for next line, waiting for completion of
a string that began with a single quote (‘'’)
Entering Queries

35.  "> Waiting for next line, waiting for completion of a
string that began with a double quote (‘"’)
 `> Waiting for next line, waiting for completion of an
identifier that began with a backtick (‘`’)
 /*> Waiting for next line, waiting for completion of a comment
that began with /*
Entering Queries

36. Entering Queries

37. Entering Queries
 mysql> SELECT * FROM my_table WHERE name = 'Smith AND age < 30;
 '>

38. Creating and Using a Database
This section shows you how to:
Create a database
Create a table
Load data into the table
Retrieve data from the table in various ways
Use multiple tables

39.  Use the SHOW statement to find out what databases
currently exist on the server
Creating and Using a Database

40.  If the test database exists, try to access it
Creating and Using a Database

41. USE
USE, like QUIT, does not require a semicolon
You can terminate such statements with a
semicolon if you like; it does no harm
It must be given on a single line
Creating and Using a Database

42. Creating and Selecting a Database
 If the administrator creates your database for you when setting
up your permissions, you can begin using it. Otherwise, you
need to create it yourself

43. Creating and Selecting a Database

44. Creating a Table
 Creating the database is the easy part, but at this point
it's empty, as SHOW TABLES tells you:

45. Creating a Table
 Creating the database is the easy part, but at this point
it's empty, as SHOW TABLES tells you:

46. Creating a Table
Create table slides (id integer, contents varchar(30), images char);

47. Creating a Table
mysql> show tables;

48. Creating a Table
mysql> describe slides;

49. Loading Data into a Table
 After creating your table, you need to populate it. The
LOAD DATA statement is useful for this
 Because you are beginning with an empty table, an
easy way to populate it is to create a text file
containing a row for each of your slide, then load the
contents of the file into the table with a single
statement

50. Loading Data into a Table

51. Loading Data into a Table
mysql> LOAD DATA LOCAL INFILE
- > 'C:Documents and SettingsUserDocumentiDidatticaceriMysqldati
‘ > slides.txt' INTO TABLE slides;

52. Loading Data into a Table
mysql> LOAD DATA LOCAL INFILE
- > 'C:Documents and SettingsUserDocumentiDidatticaceriMysqldati
‘ > slides.txt' INTO TABLE slides;

53. Retrieving Information from a Table
mysql> select * from slides;

54. mysql> select contents from slides;
Retrieving Information from a Table

55. mysql> delete from slides;
Retrieving Information from a Table

56. mysql> select * from slides;
Retrieving Information from a Table

57. Source

58. Source